What's the noun for thymic? Here's the word you're looking for.
thymus
(anatomy) A ductless gland, consisting mainly of lymphatic tissue, located behind the top of the breastbone. It is most active during puberty, after which it shrinks in size. It plays an important role in the development of the immune system and produces lymphocytes.
“Carcinogenesis, Mutagenesis, Impairment of Fertility: Long term studies with thymosin alpha 1 have not been done to determine carcinogenicity.”
“In addition, a protein called thymosin beta-4 reverses the effects of myocardial infarction in mice.”
“The use of a fertility-enhancing thymosin peptide or a fertility enhancing anti-thymosin antibody for preparing a composition for treating mammalian male infertility.”